Chich expression correctly describes force using Sl units
1 answer:
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Answer:
Xcm = 1.95 cm and Ycm = 1.76 cm
Explanation:
The very useful concept of mass center is
R cm = 1/M ∑
Where ri, mi are the mass positions of the bodies from some reference point by selecting and M is the total mass of the body.
Let's look for the total mass
M = m₁ + m₂ + m₃
M = 140 + 45 + 85
M = 270 g
Let's look for the position of each point
Point 1. top vertex, if the triangle has as side d
R₁ = d / 2 i ^ + d j ^
R₁ = (1.7 cm i ^ + 3.4 j ^) cm
Point 2. left vertex. What is the origin of the system?
R₂ = 0
Point 3. Right vertex
R₃ = d i ^
R₃ = 3.4 i ^ cm
a) The x component of the massage center
Xcm = 1 / M (m₁ x₁ + m₂ x₂ + m₃ x₃)
Xcm = 1 / M (m₁ d / 2 + 0 + m₃ d)
Xcm = d / M (m₁ / 2 + m₃)
b) Let's write the mass center component x
Xcm = 1/270 (1.7 140 + 0 + 3.4 85)
Xcm = 238/270
Xcm = 1.95 cm
c) let's find the component and center of mass
Ycm = 1 / M (m₁ y₁ + m₂ y₂ + m₃ y₃)
Ycm = 1 / M (m₁ d + 0 + 0)
Ycm = m₁ / M d
d) let's calculate
Y cm = 1/270 (140 3.4 + 0 + 0)
Ycm = 1.76 cm
Answer:
The system loses 90 kJ of heat
Explanation:
We can answer the question by using the 1st law of thermodynamics, which states that:
where
is the change in internal energy of the system
is the heat absorbed by the system (positive if absorbed, negative if released by the system)
is the work done by the system (positive if done by the system, negative if done by the surrounding on the system)
In this problem, we have:
is the work done (negative, because it is done by the surrounding on the system)
is the increase in internal energy
Using the equation above, we can find Q, the heat absorbed/released by the system:
And the negative sign means that the system has lost this heat.